ASK modulation is widely adopted in communication systems. For example, in Electronic Toll Collection (ETC) systems, a wake-up signal broadcasted by an Road Side Unit (RSU) is typically modulated with ASK.
Conventionally, to conserve power, an ASK signal is demodulated by means of Schottky Barrier Diodes (SBD) or source followers. However, SBDs are not compatible with CMOS integration while source followers can only achieve very limited gains.
Therefore, a new demodulator with low power consumption and high gain which is suitable for CMOS integration becomes highly desirable.